In thoracic surgery, the chest cavity often must be opened and the ribs retracted. Typically, oscillating saws are used to create an arcuate cut through the sternum, since it is difficult to properly close and reinforce a linear sternal cut for optimal cut planes consolidation, owing in part to the lack of a definitive reference or anchoring multiplanar structure to aid in sealing the closure. Cutting an arcuate line, however, is practically difficult and inexact with existing devices. Ideally, the sternum should be cut in a pattern where the two halves of the divided sternum can reunite in a manner that maximizes stability and surface area contact for primary osseous healing with maximal available osseous points and elements.
Freehand cutting saws or drills may be operated to cut such patterns like a triangle continuous wave that is commonly and synonymously referred to herein as “zig-zag” pattern. However, such free form incision patterns are inexact, prone to miss-cuts and suffer from vibrational deviations. Other non-articulating systems exist with tracking mechanisms that display the position and orientation of the device on a monitor. This however requires the operator to constantly check a monitor during cutting and there is little assistance provided to prevent either a miscut, inadequate cut placement, or the ability to constrain movement according to a planned and/or pre-programmed cutting pattern.
Thus, there exists a need for a method and device that assists the operator in precisely cutting the sternum in a pattern, whereupon closure, the two halves are joined to provide superior stability and increased contact surface area to promote optimal bone healing. There further exists a need for a system which prevents a drill operator from deviating from a pre-indicated planned cutting path. There also exists a need for a drilling system that allows an operator to compensate for a cutting surface's movement while maintaining a precise cutting pattern through a subject's sternum.